Wish I could say it better than the geniuses at someecards. But I can't.
Cinco de Mayo (and shouldn't all our holidays just be named after the date? So much simpler) is a Mexican celebration of a battle victory over the French.
I think we can all agree that defeating the French is something to be celebrated. No one has managed to defeat them before. Good thing Germany doesn't take this approach or there would be no Mercedes Benz.